Improvement in lamp-collars



G. W. BROWN.

LAMP-COLLARS. I $10,175,022. Patented March 21,1876.

MFEI'ERS. FHOYO-LITHOGRAPHER. WASHINGTON. D C.

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UN TED S E PATENT OFFICE.

GEORGE w. BROWN, OF FOBESTVILLE, ASSIGNOR TO THE BRISTOL BRASS IMPROVEMENT IN llAMP-COLLARS.

Specification forming part of Letters Patent No. 175,022, dated March 21, 1876; application filed February 9, 1876.

To all whom it. may concern:

Be it known that I, GEORGE W. BROWN, of Forestville, in the county of Hartfordaild State of Connecticut, have invented a new and useful Improvement in Lamp-Collars and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawing, which forms part of this specification:

To economize metal in the construction of lamp-collarsthat is, to make them of as thin sheet metal as possible-So that in the manufacture of such articles by the thousand or million there will be a material saving in expense, it has been proposed to form the screwthread within their necks or open tops by spinning, swaging, striking up, or other analogous operations, as distinguished from cutting said thread by means of a tap or otherwise, and which cutting of the thread requires a much stouter grade of. metal to be used, thereby adding to the expense, and even then giving a less prominent screw-thread than by spinning, swaging, or striking it up out of thinner sheet metal. Thus, among other methods of making lamp-collars out of very thin sheet metal, and at the same time of providing for a bold or well-defined screw-thread therein, is that described in the patent of Frank Bhind, issued June 22, 1875, in which a recessed block, divided dies, and an operat ing wedge are used for stamping the screwthread in the metal collar; also, the method described in the patent of Alvin Taplin, issued April 13, 1875, in which the blank out of which the collar is formed is threaded in the flat and afterward struck up into its final or ring form.

Both of these methods are practicable, and admit of the collars being made of very light or thin sheet metal, and so that the collar presents a bold or well-defined interior screwthread, but while the. gaining of these advantages has been a great desideratum, there has been a great disadvantage involved in the use of very light metal, inasmuch as said collar .is so limber and weak in its outer portion that it is easily injured, or its form destroyed So as to materially impair its efliciency.

M y invention obviates this defect, and at the same time preserves the economy of making the lamp-collar of very thin sheet metal by spinning, swaging, striking up, or otherwise analogously forming, as distinguished from cutting, as by a tap, the screw-thread therein, and consists in a lamp-collar having its interior screw-thread thus formed, and with its body or outer portion stiffened by means of circumferential ridges formed by throwing the metal up or in from the opposite side in the form of a groove, thus giving the collar all the advantage of one formed of thicker sheet metal, likewise contributing to its more perfect retention by the plaster ordinarily employed to hold it on the lamp, and giving a better fin ger-hold for its adjustment.

In the accompany drawing, Figure 1 represents a side view of my improved lamp-collar, and Fig. 2 a vertical section of the same.

A is the collar, which may be spun or struck up out of thin sheet metal, and the screw-thread b, within its upper open portion 01, formed by spinning, swaging, or striking up, or other analogous process, as, for instance, by threading the collar blank in the flat and afterward striking up such threaded portion into its required ring shape, as in the patent of Alvin Taplin, hereinbefore referred to. Such thin metal lamp-collar, with its well-defined screwthread, I give all the desired rigidity to, even though using a thinner metal than usual, by forming its body or outer portion 0 with circumferential ridges 6, produced by throwing the metal up or in from the opposite side in the form of a groove. This may be done by putting the collar in an expanding chuck in a lathe and applying aknurling tool or tools to its body 0, or it may be done by any other suitable means, and the ridges 6 either be arranged to project internally or externally. The ridges or projections 0, thus formed in the body 0, also serve to give a better hold of the collar on the plaster by which it is secured to the lamp.

In this way or by these means I produce a lamp-collar which, while preserving its form and admitting of being Securely retained to its place, may be made lighter and cheaper than other collars for the same purpose.

I am aware that lamp-collars having spiral screw-threads stamped in the metal, for the purpose of fitting over a similar thread on the neck of the lamp is old; but this I do not claim.

I claim- As a new article of manufacture, a lampcollar constructed of thin sheet metal. with a series of annular circumferential strengthening-ridges, e, curved shouldendat the top, and screw-threaded.- flange b, projecting downwardly from the shoulder into the collar, substantially as described.

GEO. W. BROWN.

Witnesses BENJAMIN W. HoFFmN, FRED. HAYNES. 

